Pouring control for aluminum ingots



W. M. PEAK ETAL POURING CONTROL FOR ALUMINUM INGOTS Dec. 6, 1960 3Sheets-Sheet 1 Filed Sept. 30, 1957 INVENTORS M/mm 3 4 James M09 (/ZWMJQDec. 6, 1960 w. M. PEAK ET AL 2,962,778

POURING CONTROL FOR ALUMINUM INGOTS Filed Sept. 30, 1957 5 Sheets-Sheet2 INVENTORS. ////'avfl 44 Peak Dec. 6, 1960 w. M. PEAK ET AL POURINGCONTROL FOR ALUMINUM INGOTS 3 Sheets-Sheet 3 Filed Sept. 30, 1957William M. Peak, Valleyford, Wash., and James Wade, S. 411 Sheridan,Spokane 3, Wash.

Filed Sept. 30, 1957, Ser. No. 687,319

3 Claims. (Ci. 22-79) The present invention relates to improvements inmeans for controlling the flow of molten metal from a trough into aningot mold. In the manufacture of certain metal products such as sheetmetal and the like, and particularly in the manufacture of sheetaluminum, one step of the manufacture process involves the formation ormolding of large ingots of metal which are later rolled out into thinsheets. These ingots are formed by pouring molten metal into a mold andcooling it to a solid state. The formation of the ingotis a difficultand exacting process in that an acceptable ingot must be entirelyhomogeneous, and must be uniform throughout its mass in all respects.

One of the present methods of forming a commercially acceptable ingot isto utilize a vertically shallow four sided ring mold having an open topand an open bottom, together with a vertically movable bottom closureplate below the mold. The bottom closure plate is initially brought intoposition to close the bottom of the ring and molten metal is poured intothe ring. As the metal is poured in the top of the ring, the bottomclosure is lowered away at a constant rate. The lowering is timed sothat the metal solidifies while confined within the ring mold and thesolid ingot is withdrawn from the bottom thereof. By using this methodit is :possible to form ingots of very large dimensions which arehomogeneous and uniform throughout their mass. This method successfullyovercomes the problem of non-uniformity due to unequal cooling which isencountered in molding large objects by pouring molten metal into astationary mold and allowing it to cool in the mold.

In carrying out the ingot molding process described above, it isessential that the flow of liquid into the ring mold be carefullycontrolled tomaintain the liquid level in the mold stationary. *If theflow of liquid is reduced, and'the liquidlevel in the mold drops off, orif the flow ofliquid is increased and the liquid level in the mold isallowed to rise, then the ingot withdrawn from the bottomof the moldwill not be entirely uniform. It is the principal purpose of'thisinvention to provide a control apparatus to control the flow of moltenmetalfrom a supply trough into the ring mold, to maintain the liquidinthe ring mold at a constant level. More specifically it is the purposeof this invention to provide a novel and simple device for controllingthe flow of molten metal "from asupply trough into amold which isoperably responsive. to the level of liquid in the mold to increase ordecrease the flow of metal according to variations in the liquid levelin the mold.

The nature and advantages of our invention will appear more clearly fromthe following description and the accompanying drawings wherein apreferred form of the invention is shown. It shouldbe understood,however, that "the description and drawings are illustrative only andare not intended to limit the invention except insofar as itis limitedby the claims.

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In the drawings:

Figure 1 is a perspective view illustrating an ingot mold, together witha molten supply trough, and illustrat ing our invention in place tocontrol the flow of molten metal from the trough into the mold;

Figure 2 is an enlarged vertical sectional view taken substantially onthe line 22 of Figure 1;

Figure 3 is a vertical sectional view taken onthe line 3-3 of Figure 2;and

Figure 4 is a fragmentary sectional view taken substantially on the line4-4 of Figure 2.

Referring now in detail to the drawings, we have shown, somewhatdiagrammatically, an ingot mold, generally indicated by the numeral 10,of the type currently in use in the aluminum industry for forming ingotsof large dimensions. The mold 10 comprises a four sided ring 11, the topand bottom of which are open, together with a horizontal bottom closureplate 12, mounted on the piston 13 of an hydraulic cylinder 14. Theplate 12 is adapted to be moved up and down below the ring 11 byoperation of the cylinder 14.

In the formation of an ingot, such as that indicated by numeral 15, theclosure plate 12 is initially moved up against the bottom edge of thering 11, and molten aluminum is poured into the ring 11 from the opentop. When the molten metal has reached a predetermined level in the ring11, the cylinder 14 is activated to commence lowering the closure plateaway from the ring 11 at a predetermined steady rate. Molten aluminum iscontinuously poured into the top of the ring 11 at such a rate as tomaintain the level in the ring 11. stationary. A boX like bafiie member16, having liquid discharge openings 17 at its ends, is suspended in theopen top of the ring 11 to receive the molten metal poured into the topof the ring 11 and deflect it laterally toward the ends of the ring toinsure that the ring is filled evenly. The rate at which the plate 12 islowered is determined by the rate of cooling of the molten metal, and isadjusted so that a layer of metal poured into. the ring 11 coolssufiiciently during its downward movement through the ring 11 tosubstantially solidify while still confined within the ring 11, sothatasthe closure plate 12 is lowered, a solid ingot is withdrawn from thebottom of the ring 11.

The ring 11 may, of course, be cooled, and cooling means may be providedbelow the ring 11 to lower the temperature of the solid ingot, ifdesired. No such means have been shown in the drawings, since thedetails of construction and operation of the mold 10 form no part of theinvention. Molds of the type hereinbefore described are well known inindustry.

In order to convey molten metal from the furnace (not shown) wherein itis heated to a molten state to the mold 10. trough means are provided. Asupply trough 18 is provided into which molten aluminum is spilled fromthe furnace by some suitable means. The supply trough 18 has adeliverytrough 19 connected thereto which carries the molten metal from thesupply trough 18 to the mold 10. As shown in Figure l, the deliverytrough 19 is pivotally connected to the supply trough 18 by pivot means20 whereby to be pivoted laterally to serve several molds 10.

It will be appreciated that maintenance of a constant liquid level inthe ring 11 is of utmost importance in the formation of an acceptableingot. If the level in the ring 11 is allowed to rise or fall because ofimproper adjustment of the rate of flow of metal from the trough 19, anon-uniform ingot will be produced. It is therefore necessary to provideon the delivery trough 19, means to regulate the flow of metal-therefromintothe mold 10 in response to level variations in the ring 11.

According to our invention, we accomplish this result by providing inthe bottom of the trough 19 adjacent the discharge end thereof, adownwardly directed conical spout 21 adapted to pass molten metal fromthe trough downwardly into the bafile box 16 of the mold 10. An uprightcylindrical rod 22 is provided in the trough 19 in vertical alignmentwith the spout 21. The rod 22 is smaller in diameter than the upper endof the spout 21 but greater in diameter than the lower end thereof sothat it may be lowered into engagement with the conical wall of thespout 21 to close it. The bottom end of the rod 22 is rounded orbevelled as shown in Figure 2, to seal tightly against the spout 21 whenit is lowered into engagement therewith. By moving the rod 22 verticallywith respect to the spout 21 it is posible to accurately control theflowof molten metal from the trough 19 into the bafile box 16.

To support the rod 22, we provide a frame 23 which is adapted to beclamped to the trough 19 above the spout 21. The frame 23 comprises apair of spaced apart transversely extending members 24 and 25 which havetheir opposite ends turned downwardly as shown at 26 and 27. The members24 and 25 are connected together near one end by a bar 28, and near theother end by an upstanding inverted V-shaped yoke 29. The downturnedends 27 of the members 24 and 25 have clamping bolts 30 threadedtherethrough. The frame 23 rests upon the trough 19 as shown best inFigure 1, with the members 24 and 25 extending across between the sidewalls thereof. The walls of the trough 19 are clamped between thedownturned ends 26 of the members 24 and 25 and the bolts 30 and theframe 23 is thus held securely in place.

The upstanding inverted yoke 29 on the frame 23 pivotally supports apair of control arms 31 and 32 which extend transversely over the frame23. As illustrated best in Figure 2, each of the control arms 31 and 32has a series of apertures 33 near the center thereof, one of whichreceives a pivot pin 34 secured in the top of the yoke 29. A splitclamping sleeve 35 is positioned between the ends of the control arms 31and 32 which extend over the trough 19. The sleeve 35 has outwardlyprojecting pins 36 fixed thereon as shown in Figure 4, which extendthrough one of a series of holes 37 in the arms 31 and 32 to pivot thesleeve 35 between the ends of the arms 31 and 32. The sleeve 35 isclamped around and supports the rod 22. It will be understood that withthis construction, movement of the control arms 31 and 32 about thepivot pin 34 results in vertical adjustment of the rod 22 with respectto the spout 21 and consequently, causes adjustment of the flow ofmolten metal therethrough.

In order to actuate the control arms 31 and 32 in response to levelvariations in the ring 11, a float generally indicated at 38 isprovided. The float 38 is connected to the lower end of a rod 39 whichextends upwardly between the outer ends of the control arms 31 and 32.The rod 39 has a threaded portion 39a thereon which receives a threadedsleeve 40. The sleeve 40 is provided with pivot pins 41 which arejournalled in one of a series of apertures 42 in the arms 31 and 32 topivotally connect the float rod 39 to the arms 31 and 32.

The operation of our invention is very simple. The float 38 is allowedto contact and be supported by the molten aluminum in the ring 11.. Thefloat .rod 39 and the rod 22 are then adjusted so that when the level inthe ring 11 is at the proper point, the flow of molten metal through thespout 21 is just suflicient to maintain the level in the ring 11constant as the closure plate 12 is lowered away. When these adjustmentshave been made, the apparatus will operate to maintain this levelthroughout the pouring operation. If for any reason, the level in thering 11.tends to rise, the float 38 will be elevated, and this motionwill be transmitted through the rod 39 and the arms 31 and 32 to lowerthe rod 22 and cut down the flow through the spout 21. If for any reasonthe metal in the ring drops below the proper level, the float will dropalso and raise the rod 22 to increase the flow through the spout 21. Therod 22, being thus operatively responsive to even the slightestvaraiation in the liquid level in the ring 11, operates continuously toadjust the flow through the spout 21 to maintain the proper level in themold.

It will be appreciated that since the spout 21, rod 22, and float 38 areconstantly in contact with molten aluminum, or molten aluminum alloys,the temeperature of which is considerably in excess of 650 degrees C.,they are maintained at approximately the same temperature. It has beenfound that steel possesses the proper characteristics for use at suchtemperatures, and in the aluminum industry, the molten metal carryingtroughs such as the trough 19 and pouring spouts such as the spout 21,are commonly formed of this metal. We have found, however, that the rod22 should not be made of steel. At the temperatures at which the spout21 and rod 22 are maintained, a steel rod such as the rod 22 tends tostick to the spout 21 when it is brought into contact therewith, andsome jarring force is necessary to break it away. Carbon does notexhibit this sticking tendency, and we have found that if the rod 22 isformed of this material it will move into and out of engagement with thesteel spout 21 freely, even when both are heated to the temperaturesthey attain during the pouring operation. Accordingly, the rod 22 of ourinvention is formed of carbon.

In order for our flow control device to operate, it is necessary thatthe float 38 and rod 39 be heavy enough to overbalance the weight of therod 22. The float 38, however, must be light enough to float on themolten metal in the ring 11. We have found that a hollow steel can formsa satisfactory float 38. Since the float 38 is hollow, and since it issubject to wide temperature variations, it is desirable to provide ventmeans in the float 38 to prevent undue stresses caused by air pressuretherein. This is accomplished by providing an axial venting aperture 43in the float rod 39 opening at the bottom into the interior of the float38. This aperture.

43 permits free air movement into and out of the float 38.

While we have shown the float 38 formed as a hollow steel can, we do notwish to be limited to this construction. The float 38 may also beprovided in solid form, and may be formed of carbon as well as steel.Weights, such as those indicated at 44 in the drawings may be used toobtain the proper balance.

It is believed that the nature and advantages of our invention appearclearly from the foregoing.

Having thus described our invention, we claim:

1. In aluminum ingot molding apparatus including a ring mold having anopen top and bottom, a vertically movable bottom closure plate below thering mold, means supporting said closure plate for vertical movementtoward and away from said ring mold, a baffle box suspended within thering mold, and a delivery trough for delivering molten metal through thebaflie box to the mold, the improvement in means to control the flow ofmolten metal from the trough into the mold comprising a conical spout inthe bottom of the trough, the walls of said spout converging downwardly,an upright cylindrical rod in the trough in substantial verticalalignment with the spout and extending into the spout, arm meanspivotally supporting said rod, a frame resting on the trough above thespout and having means thereon to secure it to the trough, upstandingarm support means projecting upwardly from. the frame adjacent to oneside of the trough, said arm means being pivoted intermediate the endsthereon on said arm support means at a point spaced from the rod, andfloat means in the mold supported in floating position by the moltenmetal in the mold movable vertically in response to changes in the levelof the metal in the mold, said float means being connected to the armmeans at the end thereof opposite the rod, said float means beingheavier than the rod whereby to overbalance it and to move the rodvertically with respect to the spout to vary the flow of metal throughthe spout in response to level variations of the molten metal in themold.

2. In aluminum ingot molding apparatus including a ring mold having anopen top and bottom, a vertically movable bottom closure plate below thering mold, means supporting said closure plate for vertical movementtoward and away from said ring mold, a baflle box suspended within thering mold, and a delivery trough for delivering molten metal through thebaflle box to the mold, the improvement in means to control the flow ofmolten metal from the trough into the mold comprising an elongatedtapered outlet in the bottom of the trough above the mold, the outletdecreasing in cross-section downwardly, an upright rod of uniformcross-section in substantial vertical alignment with the outlet, saidrod being movable upwardly and downwardly in the outlet to increase anddecrease the outlet area, arm means pivotally supporting said rod, aframe resting on the trough above the tapered outlet and having meansthereon to secure it to the trough, upstanding arm support meansprojecting upwardly from the frame adjacent to one side of the trough,said arm means being pivoted intermediate the ends thereof on said armsupport means at a point spaced from the rod, and float means in themold supported in floating position by molten metal in the mold andmovable vertically in response to changes in the level of the metal inthe mold, said float means being connected to the arm means at the endthereof opposite the red, the float means overbalancing the rod wherebyto move the rod vertically with respect to the outlet to increase anddecrease the outlet area in response to downward and upward movement ofthe float whereby to reduce the flow of metal from the outlet when thelevel in the mold rises and to increase the flow of metal from theoutlet when the level in the mold drops.

3. In aluminum ingot molding apparatus including a ring mold having anopen top and bottom, a vertically movable bottom closure plate below thering mold, means supporting said closure plate for vertical movementtoward and away from said ring mold, a baflle box suspended within thering mold, and a delivery trough for delivering molten metal through thebafile box. to the mold, the improvement in means to control the flow ofmolten metal from the trough into the mold comprising an elongatedtapered outlet in the bottom of the trough above the mold, the outletdecreasing in crosssection downwardly, an upright carbon rod of uniformcross-section in substantial vertical alignment with the outlet, saidrod being movable upwardly and downwardly in the outlet to increase anddecrease the outlet area, arm means pivotally supporting said rod, aframe resting on the trough above the tapered outlet and having meansthereon to secure it to the trough, upstanding arm support meansprojecting upwardly from the frame adjacent to one side of the trough,said arm means being pivoted intermediate the ends thereof on saidsupport arm means at a point spaced from the rod, and float means in themold supported in floating position by molten metal in the mold andmovable vertically in response to changes in the level of the metal inthe mold, said float means comprising a hollow metal can and an uprighttubular vent pipe fixed to said can, said vent pipe being pivoted to thearm means at the end thereof opposite the rod, the float meansoverbalancing the rod whereby to move the rod vertically with respect tothe outlet to increase and decrease the outlet area in response todownward and upward movement of the float whereby to reduce the flow ofmetal from the outlet when the level in the mold rises and to increasethe flow of metal from the outlet when the level in the mold drops.

References Cited in the file of this patent UNITED STATES PATENTS1,139,887 Mellen May 18, 1915 1,139,888 Mellen May 18, 1919' 1,893,859Gleason et al. Jan. 10, 1933 2,290,083 Webster July 14, 1942 2,356,013Sponner Aug. 15, 1944 2,639,490 Brennan May 26, 1953 FOREIGN PATENTS256,026 Switzerland July 31, 1948 52,071 Netherlands Oct. 15, 1941

